Energy storage devices, such as supercapacitors and lithium ion batteries comprise active materials, electrolytes and separators. For optimal energy storage, active materials should have large surface areas, chemical and mechanical stability, and good electrical properties, especially electrical conductivity. As such, carbon-based materials are widely used in practical and commercially-feasible energy storage devices. Modified carbon-based materials such as activated carbon, carbon nanotubes and graphene have been suggested for such applications, but are limited in their performance due to self-aggregation and the presence of micropores, both phenomena restricting ion diffusion and causing loss of active surface area.